Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
1983 GMC Forward Control 6.2 J, StandardFACTORY OEM SERVICE PROCEDURE
Injection Pump Housing Fuel Pressure
- Remove injection pump and drain all fuel. Connect an air supply line to fuel inlet fitting. Be sure air supply is clean and dry.
- Seal the return line fitting. Completely immerse pump assembly in a container of clean test oil.
- Apply 20 psi (1.4 kg/cm2 ) to pump. Leave pump immersed for 10 minutes to allow any trapped air to escape. Watch for leaks after 10 minutes.
- If no leaks are noticed after 10 minutes, reduce air pressure to 2 psi (.14 kg/cm2 ) for 30 seconds. If there are still no leaks, increase pressure to 20 psi (1.4 kg/cm2 ) again.
- If no leaks are observed, pump is serviceable. If leaks are observed, pump must be exchanged for replacement unit.
Factory Service Tools
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.